GuerrillaCyclers is a social mobile game that rewards players with points for cycling or walking around town. Players use a mobile app to track their activity, which converts the path data into points in a sports diary. The diary and points can be shared on a web portal and social networks. The goal is to encourage active and green transportation while allowing for individual and team gameplay. Data from the app is uploaded to the portal in an open format for building public datasets on transportation trends.